Thursday, June 25, 2009

From Smart Growth to Smart Shrinkage

Some smart-growth advocates are rethinking their principles after hearing that Flint, Michigan, plans to deal with its declining population by moving people from its sparsely populated neighborhoods to its more successful neighborhoods, and then restoring the abandoned neighborhoods as open space.

Smart growth has always been based on the idea that we need to accommodate population growth with minimum environmental impact by building denser, more walkable neighborhoods around the transit stops of existing cities.

But world population will peak and begin decline in a few decades. All over the world, people are moving to cities and having fewer children. The fertility rate is already below the replacement rate in the developed nations, and it is dropping rapidly in the developing nations. Because of these demographic changes, the United Nations projects that world population will grow about one-third beyond its current level, will peak in the 2050s, and then will begin a long decline.

Declining American cities, such as Flint, are early signs of a trend that will spread around the world as population growth slows. Some urban planners are already talking about how to take advantage of future population decline. For example, the Shrinking City Institute at Kent State University in Ohio says it wants to:

“explore the idea of planned shrinkage as an alternative to the quest for continuous growth. This alternative model could include the demolition or dismantling of under-utilized housing and other building stock … and downsizing of municipal infrastructure to correspond to declining population. … opportunities may arise for restoring native landscape ecologies …. Planned shrinkage can identify opportunities to establish lively and attractive development clusters … while improving air and water quality, enhancing wildlife habitat, and establishing exciting new recreation opportunities.”

The same principles of “smart growth” apply whether population is growing or shrinking. To reduce our ecological footprint, we need to build walkable, transit-oriented neighborhoods that are denser than conventional suburban sprawl.

We can see the environmental benefits very clearly if we compare neighborhoods at two different densities. One million people would take up 500,000 acres at 2 people per acre, a typical suburban sprawl density. One million people would take up only 100,000 acres at 10 people per acre, the density of the old streetcar suburbs that were popular with the American middle-class a century ago.

The denser development would benefit the environment in many ways:

Only one-fifth as much land would be developed.

Driving would be cut by more than half because of shorter distances alone. Driving could be reduced by even more, because higher density can support better transit service. There would be a dramatic reductions in gasoline consumption and greenhouse gas emissions.

Water use would be cut dramatically, because people would have smaller lawns, the biggest residential use of water.

Land for growing food would be available nearer to the city, reducing the distance that food has to be transported.

Large parks would be available nearer to the city, providing wildlife habitat and providing easily accessible recreation.

Far less land would be paved for roads and parking lots.

In reality, density could increase even more than this, because many people would want to move to urban neighborhoods rather than streetcar suburbs as the population ages and fewer households have children. With a combination of streetcar suburbs and traditional urban neighborhoods, densities could easily go up to 15 or 20 people per acre, saving as much as 90% of the land consumed by sprawl.

But it is interesting to compare streetcar suburbs with sprawl suburbs, because both appeal to the same people, and because streetcar suburbs are so obviously more livable than sprawl in addition to being more environmentally sound. It is obviously better to have a home in a neighborhood where you can walk to Main Street shopping than in a neighborhood where you must drive to a strip mall.

The smart-growth movement has already begun to make our cities more livable. New Urbanist planners have converted some strip malls to Main Streets and some regional malls to traditional town centers. Some declining, semi-abandoned inner-city neighborhoods, such as Uptown in Oakland, California, have been rebuilt in the style of traditional European neighborhoods with housing above shopping.

But it will be much harder to improve our cities in these ways after population begins to decline, when there will be little need to build new housing and shopping. If we want to transform our cities, we must focus on smart growth for the next few decades, so we can focus on smart shrinkage when population starts to decline.

Smart growth advocates would do well to talk about this larger change that includes both smart growth and smart shrinkage. They usually say that growth is inevitable and we need smart growth to reduce its impact, which makes it sound like they are calling for the lesser of two evils: any growth will damage the environment, but smart growth will damage it less. The movement would be much more appealing if they talked about the larger way in which our cities could be transformed during the coming century.

For the next few decades, we need to focus on smart growth to revitalize suburbs by replacing strip malls and shopping centers walkable neighborhoods and to revitalize urban neighborhoods by developing their parking lots, drive-ins, and abandoned sites. This smart growth will reduce the environmental impact of population growth during the relatively short time that it continues, helping us to deal with climate change, peak oil, and other ecological threats in the short run.

Later in the century, we will need to focus on smart shrinkage as population declines, developing laws and financial mechanisms that let us remove the worst sprawl and restore the land as parks and farms. Sprawl takes up so much land that a 10% population decline could let us reclaim 30% of the land that is now suburbanized in the United States. In a few generations, we could get rid of the sprawl and build cities that are sustainable in the long run.

If we do not build the smart growth during the next few decades, while there is still a need to build more housing for a growing population, we will be locked into the sprawl pattern for the indefinite future: there will be little opportunity to build more housing after population begins to decline.